| It is possible to configure an I/O Server
where the Primary I/O Device will use one protocol and the Standby
I/O Device will use another protocol. This configuration is not
supported by Citect and should not be used. The Citect Compiler
does not generate an error message if you configure this setup
however it is invalid. For example you may try to configure Citect
where the Primary protocol is a TIWAY Card to a Texas 565 PLC and
the Standby Protocol is Tiway Direct using Serial port to the same
PLC. This configuration is invalid and when the Standby I/O Device
becomes active you may get the following error messages: 'Reg Size
Too Bit n' or 'Bad data/unit n type', where n is a number. If you
don't get these error messages this configuration may appear to
work correctly, however it is unstable and may fail to operate
correctly in the future. |
